Starting apparatus for internal combustion engines



April 26, 1938. w. PFISTER 2,115,671

STARTING APPARATUS FOR INTERNAL COMBUSTION ENGINES v Filed Sept. a. 1956 s Sheets-Sheet 1 llHllllllllIllllllllllllllll'lllli lllllmllHl In veniov djlw n I April 26, 1938. W. PFISTER 2,115,671

STARTING APPARATUS FOR INTERNAL COMBUSTION ENGINES Filed Se t. 8. 1936 s Sheets-Sheet 2 'l l m lH" w. PFISTER 2,115,671 4 STARTING APPARATUS FOR INTERNAL COMBUSTION ENGINES April 26, 1938.

Filed $9131. a. 1936 s Sheets-Sheet s Patented Apr. 26, 1938 UNITED STATES 'STARTINGAPPARATUS FOR INTERNAL COMBUSTION ENGINES Willy Pflster, Stuttgart, Germany, assignor to Robert Bosch Aktiengesellschaft,

Germany Stuttgart,

Application September 8, 1936, Serial No. 99,836

13 Claims.

In starting many internal combustion engines, especially heavy oil engines, a single starting motor does not sufllce and it is known to use two starters which act on the same flywheel. In constructions of this kind, however, it is possible for one starter which is already coupled with the flywheel to drive this before the other starter becomes coupled. As a result the first starter is thus over-loaded and the object of the second starter is not attained. Moreover the gear wheel of the second starter in the attempt to engage with the flywheel gear, already set in motion by the first starter, may damage this or may itself be damaged.

The object of the present invention is to remove these disadvantages and this is done by providing a switch apparatus regulated by the two starters through which the main current for the two starters is first passed when these are coupled with the internal combustion engine.

In the accompanying drawings (Figs. 1 to 5 inclusive) five examples of construction according to this invention are shown diagrammatically.

The three first examples relate to starters in which the gear wheels of the starting mechanism are brought into engagement with the flywheel of the internal combustion engine by axial displacement of the starting armatures, whilst the fourth and fifth examples relate to starters in which the gear wheel is brought into engagement with the flywheel by screwing forward on a threaded shaft.

In Figure l, I and 2 denote the axially displaceable armatures of two starters with the main exciting windings 3 and 4 and the auxiliary exciting windings 5 and 6 respectively. In the position of rest shown, both armatures are drawn somewhat to one side, outside their exciting poles. To the armatures are respectively assigned electromagnetic two-stage switches 1 and 8 with electromagnetic coils 8 and III, which have contact bridges III and I2 and two contacts I3, I5 and I4, I6 respectively. In the first stage of the switch in which the contact bridges contact with the contacts I3, I4, both switches are locked under the influence of locking pawls I1 and I8 standing under spring pressure so that the contacts I5, It cannot be closed. As soon however,

as the armatures I, 2 are so far displaced that gear wheels 2I, 22 of the starting mechanism are completely engaged in the flywheel gear 23 of the engine to be started, the two locking pawls II, I8 are tripped by the discs I9, 20 fitted on the armatures I, 2, so that the contact bridges II, I2 are drawn by the electromagnets 9, III from Germany September 24, 1935 the first switch stage into the second switch stage. In these the two contact bridges besides contacting with the contacts I8, I4 contact also with the contacts I5, I6. 24 denotes a battery and 25 a hand switch.

In order to start the internal combustion engine the hand switch 25 is first closed, whereby the coils 9 and III of the two electromagnetic switches I and 8 of which the contact bridges II and I2 are indicated are switched on. On accountof the locking action of the two pawls II, I8, the contact bridges II, l2 pass only into the first stage of switching on in which they close the contacts I3, I4. This makes the current circuit consisting of earth, battery 24, contact I4, contact bridge I2, auxiliary exciting winding 8, armature 2 and earth. Under the influence of the auxiliary exciting winding 6 the armature 2 approaches with slow rotation to.- wards the flywheel gear 23 so that the gear wheel 22 can engage in the latter. On complete engagement the locking pawl I8 is tripped by the releasing disc 20 and as a result the contact bridge I2 by slightly tilting can be drawn into the second stage of switching on, in which it further contacts with the contact I6. This closes the following circuit:-earth, battery 24, contact I4, contact bridge I2, contact I6, contact I3, contact bridge II, auxiliary exciting winding 5, armature I and earth, andas a result the aux-. iliary exciting winding 5 of the armature I is connected to the battery and the gear wheel 2| can engage in the flywheel gear 23. On complete engagement the releasing disc I9 trips the locking pawl I1 and the contact bridge II passes into the second stage of switching on in which it further contacts with the contact I5. Hereby the two main exciting windings 3, 4 of the two starters are connected to the battery and in fact the two following circuits are made, namely earth, battery 24, contact I4, contact bridge I2, contact I6, contact I3, contact bridge II, contact I5, main exciting winding 3, armature I, earth and earth, battery 24, contact I4, contact bridge I2, contact I6, contact I3, contact bridge 45 II, contact I5, main exciting winding 4, armature 2 and earth, the second circuit being the same as the first except for the parallel circuit through main exciting winding 4. and armature 2. As is obvious, the two starters first receive their full working current only when both gears 2| and 22 are engaged in the flywheel gear. For then first the contacts I4, I2,I6 and I3, II, I5 of the two switches I and 8 are switched on in series, and closed. If the gear wheel of the first starter does not engage, then the second starter does not receive the auxiliary current necessary to engage its gear wheel. It now the gear wheel of the first starter engages while the gear wheel of the second starter for any reason does not engage, then neither of the starters obtains the main current necessary to start the engine. Thus one starter alone is therefore prevented from starting the engine.

Figure 2 shows a somewhat simplified switch plan'in which the same parts occur as in the first example. However the switching is different and a further electromagnetic switch with a coil 26 and two contacts 21 is present.

0n starting, the hand switch 25 is closed and thereby the coil 9 of the electromagnetic switch 1 switched on. The contact bridge ll of this closes the contact l3 whereby the auxiliary exciting winding 5 is connected to the battery, in the following circuit: earth, battery24, hand switch 25, contact l3, contact bridge auxiliary exciting winding 5, armature and earth.

The armature is displayed towards the flywheel gear together with its gear wheel, and the gear wheel can engage. When the gear wheel has engaged, the pawl I1 is tripped and the contact bridge passes over into the second stage of switching on, in which the contact I5 is closed. Thereby the coil ID of the electromagnetic switch 8 is connected to the battery (circuit, earth, battery 24, hand switch 25, contact l3, contact bridge contact l5, coil l0, earth). Thereupon the electromagnetic switch 8 closes its contact l4 and thi'auxiliary exciting winding 6 is connected to the battery (circuit, earth, battery 24, hand switch 25, contact l3, contact bridge contact l5, contact l4, contact bridge l2, auxiliary exciting winding 6, armature 2, earth).

The armature 2 of the second starter is then displaced together with its gear wheel towards the flywheel gear, so that the gear'wheel can the battery and receive their full working current.

The coil 26 of the electromagnetic switch is first excited when the two electromagnetic switches 1 and 6 have reached their second stage of switching in, i. e. when the two gear wheels have been engaged. On account of this the two starters can first work with full current after the engagement of the two gear wheels and start the internal combustion engine. The use'oi the electromagnetic switch 26 has the advantage that the contacts of the two electro-magnetic switches 1 and 3 built into the two starters are not loaded with the strong main current of the two starters.

The arrangement shown in Figure 3 difiers from the arrangement shown in Figure 2 in that besides the electro-magnetic switch 26 a still further electromagnetic switch 23 with the two contacts 29 is present.

The switching on is the same as in the previous ease up to the point of the engagement of the two gear wheels. It therefore the contact bridge |2 makes contact with the contact l6 then the following circuit is closed:-Earth, battery 24,

hand switch 25, contact l3, contact bridge contact l5, contact 4, contact bridge l2, contact |6, coil 26, coil 28, earth. 1

The two electromagnetic switches 26 and 28 now close their contacts 21, 21 also 29, 29 whereby the two main exciting windings 3 and 4 are connected in separate circuits to the battery 24 (circuits, earth, battery 24, contacts 29, 29 main exciting winding 3, armature earth and earth, battery 24, contacts 21, 21, main current winding 4, armature 2, earth).

The separation of the two main exciting circuits when the auxiliary exciting windings are switched on has several advantages and is especially advantageous if the two starters are of diiferent sizes.

In the apparatus shown in Figure 4, two armatures are shown provided with gear wheels which may be screwed forwards. As in Figure 1, the two main current windings are denoted by 3 and 4, the two gear wheels by 2| and 22, the flywheel gear by 23, the battery by 24 and the hand switch by 25. Moreover, four electromagnetic switches with the coils 30, 3|, 32 and 33 and the contacts 34, 35, 36 and 31 are provided. Parallel to the two contact pairs 34, 34 and 36, 36 lie two resistances 38 and 39. With the two gear wheels 2| and 22 are connected two drums 4|] and 4|, the conical peripheries of which serve as running surfaces each for a pivoted contact lever 42 or 43. These work together with a contact 44 or 45 which in the position of rest shown is opened. On engagement of the gear wheel in the flywheel gear the drums slip along the levers 42 and 43 and displace them so that they close contacts 44 or 45.

To start, the hand switch 25 is closed. Thereby the battery 24 is connected with the two electromagnetic coils 3| and 33, through which the contact pairs 35, 35 and 31, 31 are closed. There exist on account of this the two following circuits:--(1) Earth, battery 24, contacts 35, 35,

resistance 38, main current winding 3, armature I and earth, and (2) earth, battery 24, contacts 31, 31, resistance 39, main current winding 4, armature 2, earth. The two starters receive current through the resistances 38 and 39, and rotate whereby the gear wheels screw themselves along their screw shafts and engage in the flywheel gear. The current weakened by the resistances 39, 39 does not however sufilce to impart to the starters the necessary speed to start the engine. When the gear wheels are engaged, the levers 42, 43 are so far engaged that the contacts 44 and 45 are contacted whereby the following circuit is set up:--Earth, battery 24, contacts 31, 31, coil 32, lever 43, contact 45, coil3il, contact 44, lever 42, earth. By the two electromagnet coils 30 and 32, the contact pairs 34, 34 and 36, 36 are closed, and thereby the resistances 33 and 39 short-circuited. The two starters thus receive their full current, which s'uflices to start the engine. v

Since the two contacts 44 and 45 also the electromagnet coils 30 and 32 are in series, each of the two starters can only receive its full working current if the two contacts 44 and 45 are closed,

i. e. when both starters are coupled with the ings 3 and 4 being connected by another connection. To start, switch 25 is closed whereby the battery 24 is connected to the electromagnetic switch 33, thereby closing contacts 31 so that current can flow from the battery over the resistance 39 to both exciting windings 3 and 4. when both pinions 2| and 22 engage the flywheel 23, the circuit of the electromagnetic coil 32 is closed and resistance 39 will be short circuited so that both exciting windings receive full current.

Also other alterations can be made in the example shown, e. g. the contact levers of the last example can also be used with armatures which are longitudinally displaceable.

Also in starters in which the gear wheels are coupled with the engine in another manner, e. g. electromagnetically, or by .a pedal, the switch arrangements can be so provided that the starters are first only able to receive their full current when the gear wheels of all the starters are coupled to the engine.

If more than two starters are used with the same engine, the current circuits of the further starters aresimilarly closed, so that each starter only receives the main current if all the gear' wheels are engaged.

I declare that what I claim is:

1. A starting apparatus Ior internal combustion engines, comprising a plurality of starter parts, adapted for engagement with a part of the engine to be started, separate electro-motors for driving said starter parts, means for displacing said starter parts to bring these into engagement with said part of the engine to be started, and electrical means including a low power circuit, a full power circuit and switch means controlling said circuits for driving said motors, said switch means including a starting switch and electromagnetic switch means energized by said starting switch and controlled by said motors for initially supplying low power to said motors to couple said starter parts with said engine part and then to supply full power only after said parts have been coupled.

2. A starting apparatus for internal combustion engines, comprising a plurality of starter parts adapted for engagement with a part of the engine to be started, separate electro-motors for driving and displacing said starter parts, a source of current, circuit connections between said source and said motors, and circuit-controlling means for initially supplying low power to said motors to couple said starter parts with said engine part and then to supply full power only after said parts have been coupled, said means being controlled by said motors.

3. A starting apparatus for internal combustion engines, comprising a plurality .of starter parts adapted for engagement with apart of the engine to be started, separate elect'ro-motors for driving and displacing said starter parts, twostage switch mechanism for controlling said starter parts, an electric circuit including the first stage of said switch mechanism for energizing said motors to bring said starter parts in engagement with said engine part and an electric circuit including both stages of said switch mechanism for conveying main current for driving said motors and starter parts when all said starter parts are coupled with said engine part, and means controlled by said motors for preventing said switch mechanism from effectin the switching from the first stage to the second before said starter parts are coupled with said engine part.

4. A starting apparatus for internal combustion engines, comprising a pair of starter parts adapted for engagement with a part of the engine to be started, separate electro-motors for displacing said starter parts, an electromagnetic switch coupled with each electro-motonwith the switches arranged in series, and an electric circuit including said electromagnetic switch mechanism and a starting switch for energizing said switches in succession to first supply only low power to said motors until they are coupled with the engine and then to supply full power, and means controlled by said-motors for controlling said electromagnetic switches.

5. A starting apparatus for internal combustion engines, comprising a pair of driving members adapted for engagement with a flywheel of the engine to be started, separate electro-motors for displacing said driving members, a pair of electro-magnetic switch mechanisms each of two stages and each controlled-by said electro-mo'tors and electric circuits including said switch mechanisms and a starting switch for energizing said electromagnetic switch mechanisms for closing said switch mechanisms to initially merely energize said motors sufliciently to engage said gear wheels with said flywheel and then for conveying main current for driving said motors and driving members solely when both said driving members are coupled with said engine flywheel.

6. Starting apparatus for internal combustion engines comprising, a plurality of electric motors, gearing adapted to couple said motors with the engine for starting, a source of current, circuit connections between said source and said motors, and circuit-controlling means for initially supplying low power to said motors to couple said motors with the engine and then to supply full power only after said motors have been coupled with the engine, said means being controlled by said motors.

7. Starting apparatus for internal combustion engines comprising, a plurality of electric starta ing motors, gearing adapted to couple said motors with the engine for starting, a source of current, circuit connections including a low power circuit, a full power circuit and switch means controlling said circuits for connecting said source to said motors, said switch means including a starting switch and electromagnetic switch means energized by said starting switch and controlled by said motors for initially supplying low power to said motors to couple said motors with the engine and then to supply full power only after said motors have been coupled with the engine.

8. Starting apparatus for internal combustion engines comprising, a plurality of electric motors each provided with a longitudinally displaceable armature and armature shaft, a. coupling member carried by each shaft adapted to couple said motors with the engine for starting, a source of current, circuit connections including a low power circuit, a full power circuit and switch means controlling said circuits for connecting said source to said motors, said switch means including a starting switch and two stage electromagnetic switch means energized by said starting switch and controlled by said armatures for initially supplying low power to said motors to displace said armatures and couple said motors with said engine and then to supply full power only after said motors have been coupled with the engine.

9. Starting apparatus for internal combustion engines comprising a plurality of electric motors ture and armature shaft, a coupling member on each shaft adapted to engage a complementary coupling member connected to the engine, a first and second stage field winding for each motor, a starting switch, electromagnetic switch means energized by said starting switch for controlling the switching of said field windings, and means carried by said armature shafts for preventing said electromagnetic switch means from effecting the switching from the first stage field windings to the second before saidcoupling members are fully engaged.

10. Starting apparatus for internal combustion engines comprising a plurality of electric motors,

ing motors, a screw connected with each electric motor and rotatable thereby, a screw-threaded pinion movably mounted on each screw, a toothed wheel connected to the engine for engagement by said pinions, a source of current, circuit connections between said source and said motors including a resistance for each motor, means for closing the circuit through said resistances to initially supply low power to said motors to couple them with said toothed wheel, and automatic Patent No. 2,115,671.

wILLr rism. 1

CERTIFICATE OF coRaEcr'IoN.

means including contact members, one of which is actuated by each pinion, for closing another,

circuit connection which connects the motors directly with said source to supply full power to said motors to start the engine after said motors have been coupled with said toothed wheel.

12. Starting apparatus for internal combustion engines comprising a plurality of electric motors, gearing adapted to couple said motors with the engine for starting, a source of current, circuit connections between said source and said motors including a starting switch and electromagnetic switch means energized by said starting switch for initially supplying low power only to said motors, and second electromagnetic switch means energized by said first electromagnetic switch means and controlled by said motors for supplying full power to said motors after said motors have been coupled to said engine.

13. Starting apparatus for internal combustion engines comprising a plurality of electric motors, gearing adapted to couple said motors with the engine for starting, a source of current, circuit connections between said source and said motors including a starting switch and two stage electromagnetic switch means energized by said starting switch and controlled by at least one motor for initially supplying in the first stage position of said electromagnetic switch means low power only to said motors until all of said motors have been coupled to said engine, and means actuated by said motors for permitting said electromagnetic switch-means to move to the second stage position to supply full power to the motors after they have been coupled to the engine.

WILLY PFIS'I'ER.

i t ishereby certifiedthat the name-cf theass'lg'n'e'e' ingaie that numbered patent was erroneously 'de'scr ibedfand' specified as "Robert Bosch aktiengesellschaft whereas said'hanie and specified as Robert Bosch Gesells'chaft of Stuttgart, Germany,

the Patent Office should have been described mt bes'chrlnkter r 1 m 4 as shown by the r'e cor d' of a'ssignnrents in'this office; and that the said Letters Patent should be read with this correction v therein that the same may conform to the "record of the case in" si ned and sealed this 51st day of ma A.D. 1.938.

(Seal) I Henry Van A rsdale-,-; Acting Commissioner or Patents. 

